Adapt urn_resolve() invocation. Most handlers update the dict in place. A
few will return a new row however. (This can be utilized to return a copy,
instead of changing station entries → menat for user "script stations" plugin.)
check-in: 0a425cfb5d user: mario tags: trunk

Make action.cmd() more explicit again.
Introduce cmd= override flag for action.run_fmt_url().
So that specbuttons can use it instead of just interpol().
Thus the urn:/mime handlers will engage as well.
check-in: 2b300a090d user: mario tags: trunk